The Daily Mail says with Porto showing little interest in a player-exchange deal, despite claims that midfielder Anderson could be used as a makeweight, United will have to dig deep for the left-footed Colombian, who can operate on either flank or as a striker.

Rodriguez agreed to a £40million buy-out clause being included in the five-year contract he signed last summer.

Porto are determined to hold out for the full amount and have turned down a £30million offer from United, according to reports in Portugal.